The other day I ran across the site for the Seattle Ukulele Players Association, which looks like a HUGE group of uke players in Seattle. They've got one thing that every ukulele group needs: a huge sourcebook with all the songs in their repertiore. They've also got one thing that many good ukulele clubs also have: a huge sourcebook with all the songs of a NEIGHBORING ukulele club (namely, the Ukulele Club of Santa Cruz). Both of these books are available at a copy shop somewhere in Seattle; residents should check out the site for details.
We went to Seattle on our honeymoon and had a great time there. We've always said that we need to get back there at some point, so maybe if we ever do get back there we should meet up with the Seattle club. Looks like they have loads of events and meetings happening all the time, so it should be easy.